Manufacture of tetraalkyl thiuram monosulfide



Patented Nov. 9, 1948 i g 2,453,4 4 MANUFACTURE OF TETRAALKYL THIURAM MONOSULFIDE .Waltcr Arnold Robshaw, Wrexham, Wales, assignor to Monsanto Chemical Company, St:

Louis, M0,, a corporation of Delaware No Drawing. Application September 16, 1944, Serial No. 554,552. In Great Britain May 9, 19d;

"This invention relates to the manufacture of carried out by forming the mercapto compound organic monosulfides. Moreparticularly, this inin situ. vention relates to the manufacture of thiuram v Following-isa description by wayoiexample monosulfides. I of methods of carrying the invention into effect.

It has been proposed to prepare thiuram monoxdh' I i sulfides by first preparing a thiuram disulfide and l I then converting the thiuram disulfide to the cor- A 50111131011 of Sodium dlmethyl dlthlocalbaresponding monosulfide by treatment with an mate Was p p y d n u a yfl aqueous alcoholic solution of an alkali or alkaline parts by weight of q us dlmethyl amlne earth metal cyanide. in (substantially 0.25 molecular proportion) with In accordance with the present invention it has ally 20 pa s y w t of Water and now been found that a new and very convenient reacting with s a ly a ts y w s t process for the manufacture of a thiuram mono- 0f So u hydroXide (Substantially sulfide consists in oxidizing a soluble salt of a. dileclllal proportion) d 19 pa y weight of thiocarbamic i i the presence of soluble carbon disulfide (substantially 0.25 molecular cyanide Th tetra alky] th mo b ulfide proportion). To the solution of sodium dimethyl are obtained from the corresponding dialkyl didithiocarbamate so prepared a solution of 7.5 thiocarbamates by oxidation in the presence of parts y Weight of SOdlum ya l In 67 Parts asoluble cyanide, by weight of water was added andthe mixture The course of the reaction is not completely 20 Oxidized W a Solution 31 Parts y i t understood but the overall reaction is represented 0f ammomum po s t 111 125 p ts y w t-3 by the following equation: of water, allowing the temperature to rise to 50 C. The yellow crystalline product of tetramethyl thiuram monosulfide which had precipitate was filtered off, washed, and dried at 70 C.

or by or of The process may be applied to the manufacture theory 3 of monosulfides from inter alia the corresponding Example aralkyl dithiocarbamates, N-substituted cyclohexyl dithiocarbamates, heterooyclic dithiocarin g g gg gg g ii gg g i fig ij ii' z b 5:2 3;

bamates, or substitution derivatives of these ccm- Weight of 25% dimethyl amine added with Stir Poundsring and cooling. 169 parts by weight of carbon The reactlon may be carried out In aqueous or disulfide was added over half-an-hour, allowing in aqueous 21180110110 solution at temperatures the temperature to rise to C. After an the from around 15 to 100 C. carbon disulfide had reacted, 58 parts by Weight The of the mercapw-cqntammg of sodium cyanide dissolved in 232 parts by pounds which have been found suitable for use 1n Weight of Water was added 280 parts by Weight this process include those of ammonia, alkali metof ammonium persulfate di lved in 834 parts by als, or organic nitrogen bases. The cyanide which Weight of Water was then run in, checking the may that of ammoma an alkaih metal, or an 40 temperature rise at 40 C. Stirring was continued alkaline earth metal may be usedin the the for 15 minutes and then the reaction product was ical amount required by the partial equation set cooled centrifuged, Washed and dried at 0 Q out above, or m excess of this amount. Yield 218 parts by weight (93.5% theory), M. P.

Suitable oxidizing agents lnclude water-soluble C color bright yellow per-salts, such as ammonium or alkali metal persulfates, perborates, percarbonates or perphos- Example p B Hy o n p roxide in acid solution, 101- An aqueous solution of sodium dimethyl dio s acid. ferricyanides, haloge s; ypooh o tes thiocarbamate was prepared as in Example I and and hypobromites may also be used. a solution of 6.7 parts by weight of sodium cya- The oxidizing agent may be added to a solunide was added. Oxidation Was then effected tion of the mercapto salt and the cyanide or the with 14:.7 parts by weight of 30% hydrogen persolution of the mercapto salt and the cyanide may oxide (substantially 0.13 molecular proportion) in be added to the oxidizing agent. 70.8 parts by wei ht of 18% sulfuric acid (sub- Instead of starting with the preformed merstantially 0.13 molecular proportion). The prodcapto compounds, the present process may be not was filtered, washed and dried at C. The

yield of tetramethyl thiuram monosulflde was 23 I tion is not limited to the foregoing examples or description.

v The present invention is limited solely by the claims attached hereto as part of the present specification.

What is claimed is:

1. The process of manufacturing tetra alkyl thiuram monosulfides which consists in oxidizing an alkali metal salt of a dialkyl dithiocarbamic acid in the presence of an alkali metal cyanide.

2. The process of manufacturing tetra methyl thiuram monosulfide which consists in oxidizing an alkali metal salt of dimethyl dithiocarbamic acid in the presence of an alkali metal cyanide.

3. The process of manufacturing a thiuram monosulfide which consists in oxidizing an alkali metal salt of a dialkyl dithiocarbamic acid with 1 hydrogen peroxide and mineral acid in the presence of an alkali metal cyanide.

4. The process of manufacturing tetra methyl thiuram monosulfide which consists in oxidizing an alkali metal salt of dimethyl dithiocarbamic acid with hydrogen peroxide and sulfuric acid in the presence of an alkali metal cyanide.

5. The process of manufacturing tetra, methyl thiuram monosulfide which consists in oxidizing an alkali metal salt of'dimethyl dithiocarbamic acid with a soluble persulfate in the presence of an alkali metal cyanide.

WALTER ARNOLD ROBSI-IAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,682,920 Maximoff Sept. 4, 1928 1,782,111 Adams Nov. 18, 1930 1,796,972 Whitby Mar. 17, 1931 1,796,977 Bailey Mar. 1'7, 1931 2,045,888 Tschunkur June 30, 1936 

